The sl2s galaxy-scale lens sample. V. Dark matter halos and stellar imf of massive early-type galaxies out to redshift 0.8

Alessandro Sonnenfeld, Tommaso Treu, Philip J. Marshall, Sherry H. Suyu, Raphaël Gavazzi, Matthew W. Auger, Carlo Nipoti

Research output: Contribution to journalArticlepeer-review

124 Scopus citations

Abstract

We investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. We find that the dark matter mass projected within the inner 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.

Original languageEnglish
Article number94
JournalAstrophysical Journal
Volume800
Issue number2
DOIs
StatePublished - 20 Feb 2015
Externally publishedYes

Keywords

  • galaxies: elliptical and lenticular, cD
  • galaxies: evolution
  • gravitational lensing: strong

Fingerprint

Dive into the research topics of 'The sl2s galaxy-scale lens sample. V. Dark matter halos and stellar imf of massive early-type galaxies out to redshift 0.8'. Together they form a unique fingerprint.

Cite this